Thin film transistor liquid crystal display (TFT-LCD) has been a main product provided by various manufacturers of flat displays. Due to the large-scale and curved-surface trend, the performance of the TFT-LCD has been a key issue deciding whether the manufacturer can be a key player or not. Thus, quality control is a critical issue during the mass production of the TFT-LCDs.
During the mass production of TFT-LCD, one major defect is called the “Mura.” The premise is that the grayscale values of all of the RGB pixels have to be the same, however, Mura occurs when the grayscale values of a portion of RGB pixels are quite different from that of the adjacent RGB pixels. In addition, Mura may be shown in a variety of shapes, such as line-shaped, spot-shaped, or other irregular shapes. It is known that various reasons may result in Mura, such as, the assembly or formation of the color filter, the gaps between the units when the glass is installed, too large gap between the pixels, damaged panel substrate, dis-alignment caused by the optical leakage between the top and down substrates. However, due to the above reasons, mostly, the detection time and compensation time for curing the Mura are necessary, not to mention that the compensation effect may not be good enough. Thus, it is needed to apply additional image processing to the images displayed by the LCDs.